<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>受控组件</title>
</head>
<body>
    <!-- 准备一个容器 -->
    <div id="test"></div>

    <!-- 引入react核心库 -->
    <script type="text/javascript" src="../js/react.development.js"></script>
    <!-- 引入react-dom，支持react操作dom -->
    <script src="../js/react-dom.development.js"></script>
    <!-- 引入babel，将jsx转为js -->
    <script src="../js/babel.min.js"></script>
    <!-- 引入prop-types ，对标签属性进行限制 -->
    <script src="../js/prop-types.js"></script>

    <script type="text/babel">/*此处写babel*/ 
    /*
        页面中所有输入类的DOM ,随着输入,将信息维护到状态里面去,等需要用就从状态中拿,此为受控组件
    */
        class Login extends React.Component{
            //初始化状态
            state = {
                username:'',
                password:''
            }
            //表单提交的回调
            handleSubmit = (event)=>{
                event.preventDefault();     //阻止表单提交 固定写法
                const{username,password} = this.state;
                alert(`用户名是${username},密码是${password}`)
            }

            saveUsername = (event)=>{
                this.setState({username: event.target.value})
            }

            savePassword = (event)=>{
                this.setState({password: event.target.value})
            }
            //使用输入框自带 onchange事件
            render() {
                return(
                    <form onSubmit={this.handleSubmit} action="">
                        用户名: <input onChange={this.saveUsername} type="text" name="username"/>
                        密码: <input onChange={this.savePassword} type="password" name="password"/>
                        <button>登录</button>
                    </form>
                )
            }
        }

        ReactDOM.render(<Login/>,document.getElementById('test'))
    </script>
</body>
</html>